You can try something like this. First remove the grand total from rows.
From analysis tab you can do that
See you will not have any row level grand total.
Duplicate the current sheet and remove the week ending field from column shelf and Kept% from measures values then create a calc filed using below screen shot.
Drag this new calc field in measure values. Hide the headers from Theater. You'll get below view.
Now you have to do some hack. Create a dashboard and drag sheet3 first. Hide the title of the sheet and drag another sheet4 at right side hide the title. Drag a text object and Title with "Grand total". Adjust the alignment to sync the rows. You'll get the below view.
I hope this what you wanted.